Section 31E. Any health officer or board of health for any city, town or district, whose authority includes the issuance of permits for construction, maintenance or alteration of individual sewage disposal systems for residential buildings of not more than four dwelling units, shall act upon a completed application for such permit to construct, maintain, or alter such system within forty-five days from the date upon which such completed application is filed with said health officer or board of health. If a determination on a completed application is not rendered within forty-five days by the appropriate health officer or board of health, then said permit shall be deemed to have been granted.

For the purpose of this section, a completed application shall include, but not be limited to, information satisfactory to any local board of health regarding the number of deep observation holes, all percolation test results and a plan which meets the requirements of the state sanitary code and any local health regulation. Such application shall be considered filed on the date upon which a completed application is presented by the person who is seeking the permit, to the health officer, board of health or agent thereof.

For the purpose of this section, ''action on a completed application'' shall mean approval of said application and issuance of the permit to construct, maintain, or alter, or disapproval of said application with a written statement of the reasons for such disapproval. The written statement of reasons, in the case of disapproval shall be sent to the applicant by first class mail, postage prepaid and shall include the information necessary in order to ascertain why the application or the proposed subsurface sewage disposal system or both fail to comply with local or state code requirements.

Nothing contained in this section shall be deemed to exempt the applicant from the regulations promulgated under the provisions of section thirteen of chapter twenty-one A.